Awesome sauce. That ability can be used once a day per effect. Though she is very unlikely to run into a situation where she is underwater or falling from a great height to activate the waterbreathing or feather fall effects. Shame we're not using the good Silver Key class fix, or it would be a tad bit more useful. And I wouldn't have had to waste a feat on Dodge, which I always forget to declare.
...that said, I'm using O2 as my Dodge Target for a +1 to AC, please.